Think about what the class of the result is. If you don't know how to use the class function to check that, then learn to read the output of the whos command. (In fact, in newer MATLAB releases, just displaying a variable at the command line tells you the class, if it is not a double.)
Then consider if the result is stored in an integer variable, then why would you expect a non-integer result? That is, an int32 cannot represent non-integers. So MATLAB stores only the integer part, essentially rounding to the nearest integer.
double(4) / int32(3)
double(5) / int32(3)